2023 Early Hearing Detection & Intervention Conference

March 5-7, 2023 • Cincinnati, OH

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5/22/2018 | 2:00 PM - 2:15 PM | PROCESSES AND ENVIRONMENTAL CONDITIONS INFLUENCING THE STABLE ISOTOPE FRACTIONATION FACTOR (ALPHA) OF DISSOLVED OXYGEN DURING RESPIRATION | 330 B

PROCESSES AND ENVIRONMENTAL CONDITIONS INFLUENCING THE STABLE ISOTOPE FRACTIONATION FACTOR (ALPHA) OF DISSOLVED OXYGEN DURING RESPIRATION

Traditional methods to estimate metabolism are unable to track differences in ecosystem respiration occurring between day and night. New models based on oxygen stable isotope analyses are a promising tool for more precise metabolism estimates. However, these models are sensitive to the oxygen isotope fractionation factor (alpha) used, and alpha may vary among locations and organisms, and under different environmental conditions. We explored the physical-chemical processes that influence the value of alpha related to respiration. We collected rocks and water and incubated them in the dark in sealed-recirculating chambers. Chambers were placed inside temperature-controlled chambers at 13 and 20 C, and at four flow velocities. We used a microflow probe to assess water velocity profiles to indicate thickness of the diffusion boundary layer. The flow boundary was less than 1 mm thick at ? 0.5 cm/s. The value of alpha ranged between 0.985 and 0.995, increasing with flow until a threshold flow was attained and the diffusion boundary layer thickness became less defined with increasing flow. Alpha decreased with a higher temperature. Data suggest that flow and temperature need to be accounted for when using oxygen isotope to estimate respiration

Biogeochemistry
Function
Carbon

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Presenters/Authors

Flavia Tromboni (), University of Nevada, Reno, ftromboni@unr.edu;